fix(consult): 申报时段计算改为服务端预跑并走同请求缓存（BUG-957）

窗口计算挂在 agent context 缓存上，模型开口前预跑并注入 packet；工具再调用命中同请求缓存，成功次数仍为 1。

frontend/src/app/api/consult/route.ts

@@ -38,7 +38,7 @@ import { jsonForSupabaseSetupFailure } from "@/lib/api/service-unavailable";
 import { createAdminSupabaseClient } from "@/lib/supabase/admin";
 import { createServerSupabaseClient } from "@/lib/supabase/server";
 import { streamTextResponse } from "@/lib/stream-text-response";
-import { streamAgentResponse } from "@/lib/stream-agent-response";
+import { consultationPublicActivityEvent, streamAgentResponse } from "@/lib/stream-agent-response";
 import type { AgentExecutionReceipt, WorkflowReceipt } from "@/lib/consultation-agent-events";
 import { consultationComposePrompt, consultationContinuePrompt, natalConsultationThinkingPlan, type PublicThinkingSection } from "@/lib/consultation-thinking-plan";
 import {
@@ -51,6 +51,8 @@ import {
   consultationWindowPrepareStep,
   createConsultationAgentContext,
   createWindowConsultationAgentContext,
+  precomputeWindowConsultation,
+  windowPrecomputedPacketMessage,
   consultationModelStepTelemetry,
   consultationStepBudgetReceipt,
   createConsultationRuntimeHooks,
@@ -1039,7 +1041,6 @@ export async function POST(request: Request) {
         state,
       });
       const agent = getWindowJyotishAgent(selectedModel, agentContext);
-      const result = await streamWithOverflowRetry(agent, windowStreamOptions);
       const retry = async () => {
         const retried = await agent.stream([
           ...baseMessages,
@@ -1096,7 +1097,32 @@ export async function POST(request: Request) {
         requestId,
         sideEvent: titleSideEvent,
         state,
-        stream: result.fullStream,
+        warmup: async (send) => {
+          try {
+            const packet = await precomputeWindowConsultation(agentContext, {
+              question: resolvedQuestion.modelQuestion,
+              writer: {
+                custom: async (chunk) => {
+                  if (!chunk || typeof chunk !== "object") return;
+                  const value = chunk as { type?: unknown; data?: unknown };
+                  if (value.type !== "data-jyotish-activity") return;
+                  const event = consultationPublicActivityEvent(value.data);
+                  if (event) send(event);
+                },
+              },
+            });
+            baseMessages = [
+              ...baseMessages,
+              { role: "user" as const, content: windowPrecomputedPacketMessage(packet) },
+            ];
+          } catch {
+            // Leave the contract red; the model may still call the tool.
+          }
+        },
+        stream: async () => {
+          const streamed = await streamWithOverflowRetry(agent, windowStreamOptions);
+          return streamed.fullStream;
+        },
         requireTool: true,
         retry,
         retryForAnswer,